1. Field of the Invention
The present invention relates to a press casting die, and especially to a brand new structure of a press casting die with changeable male and female die cores.
2. Description of the Prior Art
The technique of press casting with a die is a conventionally used technique in manufacturing industry, e.g., using zinc magnesium alloy to produce an electronic housing with high quality, needs only to have a die well designed, the alloy can be injected with high pressure into the die to produce an article very fast. A conventional press casting die generally has a die seat at a stationary side and a die seat at a movable side thereof; the die seat at the stationary side is fixed, while the die seat at the movable side can be assembled in a movable mode, the movable side can move closer to or away from the stationary side along its moving direction to do the processes of die closing, injection and die releasing etc.
FIG. 1 shows a conventional press casting die, in which a die seat 91 at a stationary side is composed of a stationary-side fixed plate 911 and a female die core 912, the female die core 912 is locked with screws 913 in a female-die recess 914 in the stationary-side fixed plate 911; and the stationary-side fixed plate 911 is provided thereon with a material injection opening 915.
A die seat 92 at a movable side of the press casting die has a movable-side fixed plate 921 and a male die core 922 provided in opposition to the stationary-side fixed plate 911, the male die core 922 is locked with screws 923 in a male-die recess 924; and a guiding protrusion 925 is provided on the movable-side fixed plate 921 and in opposition to the material injection opening 915, the guiding protrusion 925 is provided on its lower bottom side with a guiding recess 925a in order that injected alloy can be injected therein and through a material injecting channel 922a of the male die core 922 into a die cavity between the male die core 922 and the female die core 912 to form a shaped article.
The die seat 92 at a movable side further is provided with a top plate set 926 which is limited to move between a pair of die-foot blocks 928; in releasing the die, the top plate set 926 gets close to the movable-side fixed plate 921, a plurality of pushing-out pins 927 on the movable-side fixed plate 921 will be extended through a plurality of through holes 929 of to the movable-side fixed plate 921 to push the shaped article out of the male die core 922 for collection.
In such a structure of the conventional press casting die, the average times of use before necessary changing of the male die core 922 and the female die core 912 is about 50˜80 thousands, otherwise, the surfaces of the die cavity between the die cores 922 and 912 when being used for about 80 thousand times will crack, and their outer edges will generate a phenomenon of having extreme serious rough edges; thus its material spilling area gets larger to affect the quality of the injected material, in this case, the entire die must be changed for a new one.
In the structure of the die seat 92 at the movable side, by virtue that the movable-side fixed plate 921 and the male die core 922 shall be drilled to have the through holes 929 and the drill holes, when the male die core 922 is to be changed, the movable-side fixed plate 921 must be changed too at the same time, this will increase the cost, the cost is awfully increased especially in the present days with material's prices going up to such high levels; and this further induces environmental problems, in view of these, improvement is wanted.
And more, in manufacturing some other article, with such a conventional structure of die, the whole set of die often needs to be changed. The reason of this is resided in that, when the female die core 912 and the male die core 922 respectively in the die seat 91 at a stationary side and in the die seat 92 at the movable side must be drilled to get a plurality of new screw holes to release the die; these new screw holes will overlap with the old screw holes, thus the die seat 92 at the movable side and the die seat 91 at a stationary side will be damaged and not suitable for use. In view of this, the conventional die is unable to change for a new male die core and a new female die core, and this is a problem that the present invention is to clear up.